Uh Oh! It seems to me when an "independent consultant" talks about "evaluation" in the terms of "the oldest" they're more concerned about tenure. ("How to evaluate a teacher")
Any fair evaluation of such a diverse group as a teaching staff can only be accomplished if that group trusts the process/evaluations to be fair and unbiased without agenda. They should not in any way relate to "evaluation" and years of dedicated service, to a means of balancing the budget.
Tenure is indeed a privileged status, yet it ensures quality and professionalism and gives importance to due process. I would encourage districts to use their own common sense when jumping through dictated hoops from Lansing.